Objective  To explore the strain distribution, clinical characteristics, antifungal sensitivity and risk factors of invasive Candida infection in sterile sites of hospitalized patients.

  Methods  Specimens of sterile sites from 116 inpatients were followed up and collected. A total of 80 Candida strains were obtained through fungal culture, separation and MALDI-TOF MS automatic biological mass spectrometry identification system. Antimicrobial susceptibility was tested by fungal drug sensitivity test, and the distribution, clinical characteristics and drug sensitivity characteristics of Candida strains were analyzed based on clinical data of patients; the ERG3 and ERG11 genes of azole-resistant Candida tropicalis were sequenced to investigate a possible molecular mechanism of azole resistance.

  Results  Candida albicans was the most common pathogen of invasive Candida infections (45.00%), followed by Candida glabrata (32.50%) and Candida tropicalis (13.75%). Specimen sources were mainly urine (50.00%), followed by secretions (22.75%) and blood (5.00%). Age of patients, length of hospital stay, related invasive operations and cancer were significantly associated with invasive Candida infections (P < 0.05). Amphotericin B and 5-fluorocytosine had strong in vitro antibacterial activities against Candida. Azoles had good sensitivity to most Candida strains in vitro, while the sensitivity of Candida tropicalis to azoles was generally low (form 54.50% to 81.80%), and ERG11 gene sequencing showed that there were two missense mutations (A395T and C461T) in azole-resistant Candida tropicalis.

  Conclusion  Candida albicans is predominant in inpatients with invasive Candida infections; patients′distinctive self-factors and clinical invasive intervention should be considered as the main risk factors for invasive Candida infections in sterile sites; antifungal agents commonly used in clinic showed good in vitro antibacterial activity against non-C. tropicalis Candida, while Candida tropicalis ERG11 gene mutant products (Y132F and S154F) may be related to azole resistance.